1. Field of the Invention
The invention relates to a cartridge seal device, more particularly to a cartridge seal device for a rotary shaft.
2. Description of the Related Art
A seal device is usually mounted on a stuffing box of a pumping machine so as to prevent leakage of fluid stirred in a chamber of the pumping machine due to high pressure in the chamber. When the fluid to be processed is volatile, toxic, and/or corrosive, a dual seal device should be used.
Referring to FIGS. 1 and 2, a conventional dual seal device 2 disclosed in Taiwanese Utility Model No. M204360 includes a sleeve 21 sleeved on a rotary shaft 10 of a pumping machine 1, a first seal unit 22 disposed around the sleeve 21 and within a stuffing box 12 of the pumping machine 1, a first collar 23 disposed around the sleeve 21 proximate to an end of the stuffing box 12 and connected to the first seal unit 22, a gland 24 locked to the pumping machine 1 and abutting against the first collar 23, a second seal unit 25 disposed around the sleeve 21 and within the gland 24, and a second collar 26 disposed around the sleeve 21 and outside the gland 24.
The first seal unit 22 includes a first rotary ring 221 connected to the sleeve 21 via fastening pins 223, a first stationary ring 222, and a first abutting ring 224 having a first end portion abutting against the first rotary ring 221 and a second end portion extending into the first stationary ring 222. The first collar 23 is provided with a plurality of springs 231 disposed at an end portion of the first collar 23 proximate to the first seal unit 22 and abutting against the first stationary ring 222. The gland 24 has a through hole 241 for permitting the sleeve 21 to pass therethrough, a receiving groove 242 proximate to the first collar 23 and communicated with the through hole 241, and an inlet 243 and an outlet 244 fluidly communicated with the receiving groove 242.
The second seal unit 25 includes a second rotary ring 251 surrounding and rotatable with the sleeve 21, a second stationary ring 252 disposed around the sleeve 21 and having a first end portion received in the through hole 241 and a second end portion received in the receiving groove 242, and a second abutting ring 253 having a first end portion extending into the second rotary ring 251 and a second end portion abutting against the second stationary ring 252. The second rotary ring 251 is formed with a plurality of guiding recesses 255 at an outer peripheral surface thereof. A plurality of springs 254 are disposed between the second stationary ring 252 and the gland 24.
In operation, the pressure in the pumping machine 1 will increase when the liquid in the pumping machine 1 is pumped by rotating the rotary shaft 10. At this time, the first abutting ring 224 abuts against the first rotary ring 221 by the urging of the springs 231 between the first collar 23 and the first seal unit 22, and the second stationary ring 252 abuts against the second abutting ring 253 by the urging of the springs 254 between the second seal unit 25 and the gland 24 so as to achieve a leakage proof effect. Furthermore, since the second rotary ring 251 is formed with the guiding recesses 255, a cooling fluid can be guided to flow into the receiving groove 242 via the inlet 243 and then exit from the outlet 244 fast and smoothly so as to achieve a satisfactory cooling effect.
However, the first rotary ring 221 is connected to the sleeve 21 via the fastening pins 223, and is radially urged by an inward-bent edge 212 of a collar 211 of the sleeve 21 and a washer 226 so as to be positioned around the sleeve 21 and to rotate with the sleeve 21 when the rotary shaft 20 is rotated. The first rotary ring 221 is liable to break due to the centrifugal force produced during the rotation of the sleeve 21 and the urging force from the inward-bent edge 212 and the springs 231. Furthermore, the first rotary ring 221 and the first abutting ring 224 are merely urged by the springs 231, which may cause positional deviation of the first abutting ring 224 relative to the first rotary ring 221, which in turn reduces the leakage proof effect. Additionally, the first stationary ring 222 is connected to the first collar 23 by extending guiding pieces 225 of the first stationary ring 222 through a compression ring 27 and a washer 28 and then inserting the guiding pieces 225 into positioning grooves 232 of the first collar 23. The service life of the first stationary ring 222 may be reduced due to the interference of the aforesaid complicated transmission mechanism.